Abstract
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Objectives Glucose metabolism is usually unchanged in pathophysiological states. However, this may not be the case after burn injury. In this investigation, we used FDG to study burn induced changes in cerebral and myocardial glucose metabolism.
Methods Male rats (225 to 250 g) and mice (25-28g) were subjected to full-thickness thermal injury (25% body surface). Sham treated animals served as controls. At various times after injury (rats: 6, 24 & 72h, mice: 24 & 168h) the animals were injected with FDG (rats: 100 μCi, mice: 50 µCi). One h later, the animals were sacrificed and uptake in heart & brain was measured. Results were calculated as % ID/g (mean ± sem, n=6-10/gp).
Results The FDG uptake patterns are summarized in the Table. In rat brain uptake was decreased by ~40% at 6 h (vs shams) and persisted at this level at 24 and 72 h (p<0.001). In contrast, heart uptake was dramatically elevated at all times after injury. 6h: 263% (p<0.001), 24h: 600% (p<0.001), 72h: 452% (p<0.001). In mouse brain there was a monotonic decrease in uptake; 38 % at 24 h (p<0.001) and a further decrease by 57 % at 168 h (p<0.001 vs sham, p<0.01 vs 24 h). In contrast, heart uptake had a monotonic increase; 164% at 24 h (p<0.001) and 375% at 168 h (p<0.001 vs sham, p<0.05 vs 24 h). In addition, observation of the animals revealed signs of cerebral dysfunction, including: lethargy, difficulty in righting and disorientation.
Conclusions Burn injury results in decreased cerebral and increased myocardial uptake of FDG. These findings could have important implications for future studies of burn induced encephalopathy and alterations in myocardial metabolism in burn patients..
- © 2009 by Society of Nuclear Medicine